1kwu
Rat mannose binding protein A complexed with a-Me-Man
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OverviewOverview
Mannose-binding proteins (MBPs) are C-type animal lectins that recognize, high mannose oligosaccharides on pathogenic cell surfaces. MBPs bind to, their carbohydrate ligands by forming a series of Ca(2+) coordination and, hydrogen bonds with two hydroxyl groups equivalent to the 3- and 4-OH of, mannose. In this work, the determinants of the orientation of sugars bound, to rat serum and liver MBPs (MBP-A and MBP-C) have been systematically, investigated. The crystal structures of MBP-A soaked with monosaccharides, and disaccharides and also the structure of the MBP-A trimer cross-linked, by a high mannose asparaginyl oligosaccharide reveal that monosaccharides, or alpha1-6-linked mannose bind to MBP-A in one orientation, whereas, alpha1-2- or alpha1-3-linked mannose binds in an orientation rotated 180, degrees around a local symmetry axis relating the 3- and 4-OH groups. In, contrast, a similar set of ligands all bind to MBP-C in a single, orientation. The mutation of MBP-A His(189) to its MBP-C equivalent, valine, causes Man alpha 1-3Man to bind in a mixture of orientations., These data combined with modeling indicate that the residue at this, position influences the orientation of bound ligands in MBP. We propose, that the control of binding orientation can influence the recognition of, multivalent ligands. A lateral association of trimers in the cross-linked, crystals may reflect interactions within higher oligomers of MBP-A that, are stabilized by multivalent ligands.
About this StructureAbout this Structure
1KWU is a Single protein structure of sequence from Rattus norvegicus with MMA, CA and CL as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Orientation of bound ligands in mannose-binding proteins. Implications for multivalent ligand recognition., Ng KK, Kolatkar AR, Park-Snyder S, Feinberg H, Clark DA, Drickamer K, Weis WI, J Biol Chem. 2002 May 3;277(18):16088-95. Epub 2002 Feb 15. PMID:11850428
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